1. Field of the Invention
This invention provides a novel tray for support, transport and storage of photovoltaic cells, such as solar cells, which permits processing and testing of such cells, and including a novel mold for producing such tray, the method of making the tray, and means facilitating stacking the trays containing solar cells for storage or further processing.
2. Brief Description of the Prior Art
Solar cells are very thin and fragile, and may be of the order of 8 mils thick and in many cases may be as small as 1 to 2 mils thick. Consequently, in the usual practice, there is a great amount of breakage during processing and testing of such cells. This results in a high waste cost, and substantially increases the final cost of the solar cells.
Solar cells which are used in outer space must be relatively thin for both performance and reduced weight. Even terestrial cells must be made of a thinner construction in order to become economically feasible in many applications. Futher, Gallium Arsenide and similar III-V materials are replacing silicon as the active cell material and in many cases are more fragile than silicon.
Present practice for testing solar cells is to place an inividual cell on a copper block in a test area, such copper block typically containing one set of leads on the underside of the block which is automatically attached to one side of the cell. Therafter, leads are placed on the cell which is located on the copper block. The cell must be manually placed on and removed from the block and placed in a retainer or box containing solar cells having the same electrical characteristics. This handling of the solar cells results in a substantial amount of damage and breakage of the solar cells. This is a very labor intensive procedure which not only is inefficient, but requires a substantial amount of time for the operator to accurately position the solar cell on the copper block for proper testing. It is of critical importance in the solar cell testing operation to accurately position the cell on the block in order to obtain an accurate test reading. Further, only one solar cell can be processed on the block at any one time.
Further, the excessive amount of handling of the solar cells when employing the copper block not only results in substantial breakage, but such handling, in addition, often results in contamination and destruction of the cell, since once contaminated it is virtually useless. To avoid such contamination, the operator must use special handling gloves in many of the testing operations.
Accordingly, a primary goal of much research effort has been to reduce substantially the amount of manual involvement in the processing and testing of photovoltaic or solar cells. This is necessary in order to reduce the amount of breakage and the cost involved in such processing and testing. The main difficulty in this area is due to the low weight and thin characteristics of solar cells, which therefore renders them very fragile. Another goal has been to reduce the amount of contamination of the solar cells and to reduce the need of cumbersome gloves used by operators during testing and processing. A particular need has been the ability to test and process different sized solar cells simultaneously and to store and package such different sized solar cells. This permits satisfying those users and customers who desire one size of solar cell for a specific purpose while others want a different size solar cell. Thus, while there are not standard sizes of solar cells, it is desirable to handle all known incrementally different sizes of solar cells.